JP5934105B2 - Containers and tanks with automatically controlled heating elements - Google Patents

Description

  The present invention is a container for holding a large amount of fluid in a tank, the container for heating a first resistance element for heating the first part of the tank and a second part of the tank. And a second resistance element, wherein the second resistance element has a positive temperature coefficient.

  U.S. Patent No. 6,053,077 to Starck discloses a heating system for a liquid transport system, in particular for a urea supply system in a catalytic converter of an internal combustion engine. The system by Starck comprises a filter heater and a tank heater, both of which are of the resistive type. The filter heater is formed by heating a part of a connection line that supplies current to the PTC element of the tank heater. In this structure, a filter heater and a tank heater are provided as two series resistance elements. The tank heater includes a PTC element and controls the amount of current flowing in the series circuit. The purpose of the system by Starck is to fully heat both the filter and the tank, ensuring that the urea solution is liquid even if the temperature is below the freezing temperature of the urea solution, while at the same time reaching the desired temperature. At that point, avoid overheating or unnecessary power consumption by the heater. The known circuit achieves the desired effect by using a PTC element in a second heater placed in series with the first heater, and therefore based on the temperature resistance characteristics of the PTC and the nature of the series circuit. Limit the current in both heaters.

  Prior art solutions do not provide sufficient freedom in adjusting the respective amount of power consumed in different parts of the tank, such as filter heaters and tank heaters.

US Patent Application Publication No. 2009/0078692

  The present invention overcomes this problem by providing an additional degree of freedom in structure, represented by a resistor called a third heating element.

Therefore, a container for holding a large amount of fluid in the tank is advantageously provided, said container heating a first resistance element for heating the first part of the tank and a second part of the tank. A second resistance element, the second resistance element has a positive temperature coefficient, and the container further includes a third resistance element for heating the second portion of the tank. The second resistance element and the first resistance element form a parallel circuit, and the third resistance element is connected in series with the parallel circuit.

  Resistance heating elements having a positive temperature coefficient are well known in the art. The term “PTC material” is understood to include any material whose electrical resistance increases substantially with increasing temperature. In particular, materials whose electrical resistance increases more than twice over the temperature range between -11 ° C and + 50 ° C may be advantageously used in the present invention. The PTC element may comprise a composite material of metallic or non-metallic elements. The PTC element may include a semiconductor.

  A further advantage of the circuit presented here is that the heater does not substantially shut off as contemplated by prior art solutions, but the resistor is not affected even when the PTC element reaches a very high resistance value. It will continue to operate at the rate specified by the choice.

  In one embodiment, the first resistance element is installed outside the container, and the second resistance element and the third resistance element are installed inside the container. In a special embodiment, the second resistance element is placed on the tank accessory. In a more particular embodiment, the accessory is a pump.

  In one embodiment of the container according to the invention, the second resistance element is coated on the outside with a thermoplastic material.

  According to another aspect, an automotive fluid tank comprising a container according to the present invention is provided. In one embodiment, the container is located substantially at the bottom of the automotive fluid tank.

According to yet another aspect, use of a circuit in an automotive fluid tank is provided, the circuit heating a first resistance element for heating the first portion of the tank and a second portion of the tank. A second resistance element for heating, wherein the second resistance element has a positive temperature coefficient, and a third resistance element for heating the second portion of the tank, The second resistance element and the first resistance element are connected in parallel, and the third resistance element is connected in series with the second resistance element and the first resistance element.

  In one embodiment of the use of the present invention, the automotive fluid tank is a tank for holding a urea solution.

  Several embodiments of apparatus and / or methods in embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

1 shows a container for urea with a flexible heater according to the prior art, in which a heating element according to the invention is used. Fig. 4 shows an embodiment of a container with a heating element according to the present application, using a heating element according to the present application, in which the heating element according to the present invention is used. FIG. 2 is a circuit diagram of an electrical circuit for a heating element according to the present invention. FIG. 4 is a power consumption diagram for the various heating elements shown in FIG. 3.

  FIG. 1 shows a container 1 having a urea tank and a flexible heating means 2 according to the prior art. A storage and / or injection system if the heating element 2 is used to avoid freezing in an automotive fluid tank, for example a tank for holding a urea solution as used in a displacement reduction system The functional accessories 10 are advantageously installed in the container 1. The functional accessory 10 may comprise a pump, a level gauge, a temperature sensor, a property sensor, a pressure sensor, a pressure controller or similar equipment. The container 1 includes a base plate or a mounting plate and a peripheral portion having an arbitrary shape. By installing the functional accessory 10 in the container, the functional accessory is supplied with the desired automotive fluid as soon as the container contents reach a sufficiently high temperature to ensure fluidity. May be. For example, if the tank is intended to store a water / urea solution of a eutectic mixture, the container contents need to be heated to -11 ° C., the melting point of such a solution.

  FIG. 2 shows an embodiment of a container according to the invention. A container 101 shown in FIG. 2 is a container for heating a part of a solution in an automobile fluid tank, for example, a urea solution tank. The container 101 comprises a flexible heating element having at least one resistance wire 102, which generates heat in response to an electric current. Advantageously, the resistance wire 102 is formed from a copper nickel alloy or stainless steel.

  The resistance wire is guided by guide means 103 acting at several remote locations along the length of the wire and defines a heating surface which is partly located inside the container and partly outside the container. To do. In this way, the material inside the container 101 is heated to a temperature that ensures fluidity, thus ensuring sufficient supply of liquid material to any functional accessories installed inside the container 101. However, if necessary, the material directly surrounding the container 101 is already preheated to compensate for the heat of the amount of material present in the container 101.

  In this embodiment, the guide means 103 is a plastic strip. Alternative guide means are contemplated including plastic or metal mesh. Metal meshes have the advantage of being self-supporting and allowing heat conduction. The conductive wire 102 may itself be in the form of a metal mesh.

  In this embodiment, the guide means 103 is applied such that a part of the resulting heating surface outside the container is substantially crinoline-shaped. With respect to this shape or another shape that is substantially circularly symmetric, the resistance wire 102 is bent along a helical trajectory, or a plurality of lengths of resistance wire 102 are placed substantially concentrically.

  Other shapes may be formed in a similar manner. Therefore, the surface to be created is not limited to a flat surface or a modified example involving a flat surface, and may show bent portions along several axes. Thus, for example, a spherical surface is possible.

  The heating surface is attached to the container 101 by fixing means 104 to ensure that the position of the heating surface is in place during use.

  FIG. 3 is a circuit diagram showing advantageous electrical interconnection of different parts of the heating element according to the invention. The power source P is any suitable current source known to those skilled in the art. Elements R1, R2 and R3 are heating elements as will be described below.

  Resistor R1 represents a first heating element, preferably a first length of resistive wire 102, which is external to the container 101, ie, included in the first portion of the heating surface as described above. .

  The element R2 is an element for controlling the power distribution between the first part and the second part of the heating surface.

  Resistor R3 represents a third heating element, preferably another length of resistance wire 102, which is within container 101, ie, included in the second portion of the heating surface as described above.

  In an ideal model, element R2 is a suitable combination of components that are either considered as switches or work together as switches, which when closed closes resistor R1 and thus heats up. Prevent heating by the first part of the surface. This model is a system that depends on whether the heating element is in two stages, i.e. the first stage with the switch R2 closed and only the interior of the container 101 is heated and a heated or liquid substance is available. Deployed in a first stage that allows for rapid start-up and a second stage that opens switch R2, in which the peripheral area outside the container 101 is also heated during the second stage. Clarify the benefits of

  In one embodiment, element R2 is a resistor that is placed inside the container and has a positive temperature coefficient. Element R2 is included in the second portion of the heating surface as described above. The advantage of this embodiment is that the steps described above occur automatically and in a step-wise manner. As the interior of the container 101 heats up, the resistance of element R2 increases, thus slightly increasing the available current through resistor R1. The heating of the element R2 corresponds to the ideal switch opening in steps.

Also, the use of the circuit of FIG. 3 where the symbol R2 is a resistor having a positive temperature coefficient (PTC) is advantageous in other types of heaters other than the heaters described above. In a general way, resistor R3, the interior near the container is, there namely essential accessory, for example a heating element that is on the pump, the resistor R1 represents a heating element that is external to the container.

  Therefore, a container for holding a large amount of fluid in the tank is advantageously provided, said container heating the first resistance element R1 for heating the first part of the tank and the second part of the tank. A second resistance element R2, and the second resistance element has a positive temperature coefficient, and the container further includes a third resistance element R3 for heating the second portion of the tank. The second resistor element R2 and the first resistor element R1 form a parallel circuit, and the third resistor element R3 is connected in series with the parallel circuit.

  In one exemplary embodiment, the symbol R3 is a substantially 1Ω resistor, the symbol R1 is a substantially 3Ω resistor, the symbol R2 has a resistance value of 1Ω at an initial low temperature and later operation. It is a PTC element having a resistance value of 3Ω substantially at temperature. By applying a 12V power supply commonly available for motor vehicles to the circuit as shown, the container will have a power of R3 to 47.0 W and a power of R2 to 26.4 W, ie a total of 73. Receive 4W early. When the operating temperature is reached, the container receives only R3 to 23.0 W and R2 to 17.3 W, ie 40.3 W in total. The rest of the tank initially receives 8.8 W of power from symbol R1, which increases to 17.3 W when symbol R2 reaches operating temperature.

  In another exemplary embodiment configured to initially consume about 100 W of total power, both symbols R1 and R3 have a resistance value of 0.95Ω. The symbol R2 is selected to have a resistance value of 1.0Ω at an initial low temperature and a resistance value of 2.8Ω at a later operating temperature. When a 12V power supply is applied, the container initially receives power from R3 to 67.4W, and power from R2 to 16.8W, ie, 84.2W in total. When the operating temperature is reached, the container receives only R3 to 49.9W, and R2 to 9.5W, i.e. only 59.4W in total. The rest of the tank initially receives 16.8 W of power from symbol R1, which increases to 27.6W when symbol R2 reaches operating temperature. This power consumption transition is shown in the diagram of FIG. The horizontal axis of this diagram represents the resistance value R2. When the temperature rises with time due to the influence of the operation of the heating element, since the sign R2 has a positive temperature coefficient, the temperature rises and the resistance value of the sign R2 increases, so the horizontal axis of the diagram is the time axis Is interpreted as equivalent to However, the exact time dependence depends on the thermal characteristics of the environment in which the heating element is installed and on the actual temperature dependence of the resistor R2.

  In the above embodiment, the initial low temperature is −11 ° C. and the subsequent operating temperature is between 40 ° C. and 50 ° C. The total amount of power consumed by the various heating elements of the container according to the present invention is preferably selected according to environmental conditions and regulatory standards applicable to the market in which the system is used.

  The PTC element in the container according to the invention is preferably shielded from the fluid contained in the container. For this purpose, the PTC element is preferably coated on the outside with a suitable thermoplastic material during or after manufacture of the container. The selected thermoplastic material must be able to withstand the temperature range in which the heating element operates, preferably between -40 ° C and + 50 ° C.

  Furthermore, it is necessary to ensure that the connection between the PTC element and the wire that supplies current to the PTC element is electrically isolated and leak-free. Such connections can be obtained using shrink tubing or mechanical pressure connectors made of a suitable elastomer or polymer compound.

  Advantageously, the container according to the invention is preferably provided inside a tank of a passenger car, for example an automobile fluid tank. For optimal operation, the container is located at the bottom of the tank or at least in the low position of the tank, and most of the fluid is naturally in the container due to gravity. The outer part of the flexible heating element advantageously extends around the container so as to ensure a supply of preheated fluid towards the container.

  The tentacle of the heating surface or the length of the resistance wire extends within a distance away from the center of the cavity or tank, avoiding the presence of frozen material at these locations for a long time.

  The tentacles of the heating surface or the length of the resistance wire extend in or around the pipes and conduits that are part of the fluid transport system into or out of the tank and are Prevents pipes and conduits from becoming blocked.

  In one embodiment, the heating surface is configured to be foldable, preferably like an umbrella. This embodiment has the advantage that the heating element is combined with the container already in the tank by inserting the heating element in a folded form in the tank and placing it inside the tank. .

  The present invention has been described above with respect to several exemplary embodiments. These embodiments are intended for illustrative purposes and do not limit the invention. The protection scope of the present invention is defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 Container, 2 Flexible heating means, 10 Functional accessories, 101 Container, 102 Resistance wire, 103 Guide means, 104 Fixing means, P power supply, R1 1st resistance element, R2 2nd resistance element, R3 3rd resistance element

Claims (6)

A container for holding a large amount of fluid in a tank,
The container is
A first resistance element for heating the first portion of the tank;
A second element for heating the second portion of the tank, the second element having a positive temperature coefficient;
A third resistance element for heating the second portion of the tank;
With
The second element and the first resistance element form a parallel circuit, and the third resistance element is connected in series to the parallel circuit,
At a first time corresponding to the start of heating, the second element has a first resistance to consume first power in the container, and at a second time later, the second element A second resistor for consuming the second power in the container, wherein the second power is lower than the first power, so that the power consumed in the tank is less than the first time point; also rather low in the second time point,
The container is characterized in that the first resistance element is installed outside the container, and the second element and the third resistance element are installed inside the container . Before Stories second element is a container according to claim 1, characterized in that it is installed on the tank fittings. The container according to claim 2 , wherein the accessory is a pump. The container according to any one of claims 1 to 3 , wherein the second element is coated on the outside with a thermoplastic material. An automotive fluid tank comprising the container according to any one of claims 1 to 4 . 6. The automotive fluid tank according to claim 5 , wherein the container is installed substantially at the bottom of the automotive fluid tank .